Pressure Decay Leak Check Method and Apparatus

Abstract

Refrigerant recovery unit is provided that includes steps to test for refrigerant leaks. The steps include providing a close loop with the hoses that connect to a refrigerant system, measuring the ambient temperature, calculating the vapor pressure with the ambient temperature, calculating the test pressure as a percentage of the vapor pressure, filling the unit with the refrigerant, and performing a pressure leak test.

1 . A method of performing a pressure leak test on a refrigerant recovery unit, comprising the steps of:
 measuring an ambient temperature with a temperature sensor controlled by a controller of the refrigerant recovery unit;   determining a saturated vapor pressure with the measured ambient temperature using the controller;   determining a test pressure as a percentage of the determined saturated vapor pressure using the controller;   measuring a first pressure in the refrigerant recovery unit with a pressure sensor controlled by the controller; and   determining if the refrigerant recovery unit has passed the pressure leak test with the controller.   
     
     
         2 . The method of  claim 1  further comprising the steps of:
 determining if the measured first pressure of the refrigerant recovery unit is above the determined test pressure using the controller; 
 determining a pressure leak test time based on the determined test pressure; and 
 running the pressure leak test based on the determined pressure leak test time. 
 
     
     
         3 . The method of  claim 2  further comprising the steps of:
 performing a recovery function if the measured first pressure of the refrigerant recovery unit is above the determined test pressure; and 
 cycling refrigerant in the refrigerant recovery unit until the refrigerant recovery unit reaches the determined test pressure. 
 
     
     
         4 . The method of  claim 1  further comprising the steps of:
 determining if the measured ambient temperature is below 10° C.; and 
 alerting a user that the ambient temperature is too low to run the pressure leak test when the measured ambient temperature is below 10° C. 
 
     
     
         5 . The method of  claim 1  further comprising the steps of:
 determining if a measured tank pressure is above the determined saturated vapor pressure; and 
 alerting a user that the measured tank pressure is too high to run the pressure leak test when the measured tank is above the calculated saturated pressure. 
 
     
     
         6 . The method of  claim 2  further comprising the steps of:
 allowing the refrigerant recovery unit to stabilize; 
 measuring a second pressure of the refrigerant recovering unit with the pressure sensor; and 
 saving the second pressure of the refrigerant recovery unit into a memory, wherein the refrigerant recovery unit passes the pressure leak test if a third measured pressure of the refrigerant recovery unit does not decrease beyond a predetermined amount from the saved the second measured pressure of the refrigerant recovery unit. 
 
     
     
         7 . The method of  claim 6 , wherein the predetermined amount is about 0.20 bar. 
     
     
         8 . The method of  claim 2  further comprising the steps of:
 allowing the refrigerant recovery unit to stabilize; 
 measuring a second pressure of the refrigerant recovering unit with the pressure sensor; 
 saving the measured second pressure of the refrigerant recovery unit into a memory, wherein the refrigerant recovery unit fails the pressure leak test if a third measured pressure of the refrigerant recovery unit decreases beyond a predetermined amount from the saved second measured pressure of the refrigerant recovery unit. 
 
     
     
         9 . The method of  claim 8 , wherein the predetermined amount is about 0.20 bar. 
     
     
         10 . A method of performing a pressure leak test on a refrigerant recovery unit, comprising the steps of:
 measuring an ambient temperature with a temperature sensor controlled by a controller of the refrigerant recovery unit;   determining a saturated vapor pressure with the measured ambient temperature using the controller;   determining a test pressure as a percentage of the determined saturated vapor pressure; and   determining if the refrigerant recovery unit has passed the pressure leak test with the controller.   
     
     
         11 . The method of  claim 10  further comprising the steps of:
 determining a pressure leak test time based on the determined test pressure; and 
 running the pressure leak test based on the determined pressure leak test time. 
 
     
     
         12 . The method of  claim 11  further comprising the steps of:
 measuring a first pressure in the refrigerant recovery unit with a pressure sensor controlled by the controller; 
 determining if the measured first pressure of the refrigerant recovery unit is above the determined test pressure using the controller; and 
 reducing the measured first pressure of the refrigerant recovery unit if the measured first pressure is above the determined test pressure. 
 
     
     
         13 . The method of  claim 10  further comprising the step of:
 cycling refrigerant in the refrigerant recovery unit until the refrigerant recovery unit reaches the determined test pressure. 
 
     
     
         14 . The method of  claim 10  further comprising the steps of:
 determining if the measured ambient temperature is below 10° C.; and 
 alerting a user that the ambient temperature is too low to run the pressure leak test when the measured ambient temperature is below 10° C. 
 
     
     
         15 . The method of  claim 10  further comprising the steps of:
 determining if a measured tank pressure is above the determined saturated pressure; and 
 alerting a user that the measured tank pressure is too high to run the pressure leak test when the measured tank pressure is above the determined saturated vapor pressure. 
 
     
     
         16 . The method of  claim 11  further comprising the steps of:
 allowing the refrigerant recovery unit to stabilize; 
 measuring a second pressure of the refrigerant recovering unit with the pressure sensor; and 
 saving the second pressure of the refrigerant recovery unit into a memory, wherein the refrigerant recovery unit passes the pressure leak test if a third measured pressure of the refrigerant recovery unit pressure does not decrease beyond a predetermined amount from the saved second measured pressure of the refrigerant recovery unit. 
 
     
     
         17 . The method of  claim 16 , wherein the predetermined amount is about 0.20 bar. 
     
     
         18 . The method of  claim 11  further comprising the steps of:
 allowing the refrigerant recovery unit to stabilize; 
 measuring a second pressure of the refrigerant recovering unit with the pressure sensor; 
 saving the second pressure of the refrigerant recovery unit into a memory, wherein the refrigerant recovery unit fails the pressure leak test if a third measured pressure of the refrigerant recovery unit pressure decreases beyond a predetermined amount from the saved second measured pressure of the refrigerant recovery unit. 
 
     
     
         19 . The method of  claim 18 , wherein the predetermined amount is about 0.20 bar. 
     
     
         20 . A refrigerant recovery unit having a pressure leak test, comprising:
 a recovery circuit configured to recover a refrigerant from a refrigerant system;   a charging circuit configured to charge the refrigerant into the refrigerant system;   a recycling circuit configured to recycle refrigerant recovered from the refrigerant system;   a refrigerant storage tank in fluid communication with the recovery, charging and recycling circuits; and   a controller that controls the recovery, charging and recycling circuits, wherein the controller performs the following steps:
 measuring an ambient temperature with a temperature sensor; 
 determining a saturated vapor pressure with the measured ambient temperature; 
 determining a test pressure as a percentage of the determined saturated vapor pressure; 
 measuring a first pressure in the refrigerant recovery unit with a first pressure sensor; 
 determining if the measured first pressure of the refrigerant recovery unit is above the determined test pressure; and 
 determining if the refrigerant recovery unit has passed the pressure leak test. 
   
     
     
         21 . The refrigerant recovery unit of  claim 20 , wherein the controller further perform the following steps:
 determining a pressure leak test time based on the determined test pressure; and   running the pressure leak test based on the determined pressure leak test time.   
     
     
         22 . The refrigerant recovery unit of  claim 20 , wherein the refrigerant storage tank is coupled to a second pressure sensor, wherein the second pressure sensor communicates with the controller. 
     
     
         23 . The refrigerant recovery unit of  claim 20  further comprising of hoses configured to couple to hose couplers to form a closed loop with the refrigerant recovery unit.